Internal-combustion engine



Aug. 20, 1929.

o. HETLESATER 1,725,139

' INTERNAL COMBUSTION ENGINE Filed March 22, 1925 F:% O/af f/et/esater ATTORNEY INVENTOR Patented Aug. 20, 1929.

UNITED STATES PATENT OFFICE.

MOTORS CORPORATION, TON.

OF SEATTLE, W'ASHINGTON, A CORPORATION OF WASHING- INTERNAL-COMBUSTION ENGINE.

Application filed March 22, 1926. Serial No. 96,432.

This invention relates to internal combustion engines of the two-cycle type.

An objectof the invention is to provide an engine of this character having every advantage of a four-cycle engine and be more efficient and economical in the con sumption of fuel.

Another object is to provide a twocycle engine wherein the supply of fuel is regulated to control the speed from high to low,

or vice versa, without impairing the explosive value of the fuel charges.

More specific objects and advantages of the invention will appear in the following description The invention is illustrated in the accompanying drawing, in which,

Figure 1 is a vertical longitudinal section of an engine embodying my invention; Fig. 2 is a vertical section taken substantially on broken line 22 of Fig. 3; Fig. 3 is a horizontal section on broken line 8--8 of Fig. 1; and Fig. 4 is a detail vertical section taken on broken line 4l of Fig. 3.-

' In said drawing, the reference numeral 5 represents the power cylinder and. 6 is the charging cylinder of my improved engine, said cylinders being formed desirably as a single block integral with or rigidly secured to a base member 7. Provided in the respective cylinders are pistons'8 and 9, the wrist pins 8 and 9 thereof being connected by connecting rods 10 and 11 with cranks 10 and 11 of a crank-shaft 12 which is journaled in bearings 13 provided in the engine base 7. As illustrated in Fig. 2, said cranks are disposed to have the pistons be at opposite ends simultaneously of the re spective strokes, best results being had by giving the crank 10 of the power piston a lead of approximately .circular measure.

As shown, the bore of the charging cyl inder 6 is of greater diameter than the power cylinder bore so as to enable the piston of 7 the former to operate with the shorter stroke.

Said power cylinder is provided in its periphery with anintake port 14 disposed helically with respect to the cylinder axis and is arranged to have its upper end terminate in proximity of the upper end of the cylinder bore.

The exhaust port or ports 15 are disposed at a lower elevation than said intake port and at the opposite side desirably of the cylinder.

The charging cylinder 6 is provided near the upper-end of its bore with one or more lntake ports 16 which are relatively wide horizontally and contracted vertically. In the side opposite the intake port 16, the bore of the charging cylinder is provided with a second port 17 which, for convenience of description, will hereinafter be termed the out let port. This port, as shown in Fig. 4, is located at a lower elevation than the intake port.

Located below said outlet port 17, the charging cylinder is provided with a port 18 making, upon occasion, communication with said power cylinder through the port 14 through the medium of by-passage 18 -49 of which the part 19 constitutes a branch of a passage 19 leading from the port 17. As shown in Fig. 8 the passage 19 is arranged to deliver combustion gases somewhat tangentially and upwardly into the power cylinder thus producing an upwardly directed whirling motion of the mixture of air and fuel gas within the power cylinder.

20 represents a by-pass valve, of the rotary type preferably, mounted within a casing 21 which is secured to the cylinder body.

Said by-pass valve is provided with a passage 22 arranged to be brought, selectively, into and out of communication with the parts 18"19 of said by-passage.

The by-pass valve 20 is regulated manually as, for example, by means of a controlling handle 23 provided upon the valve spindle 24 Fig. 3.

The piston 9 of the charging cylinder is of a substantially hollow cylindrical shape having adjacent its lower end a horizontal partition 25, Fig. 4. In the peripheral wall or flange 26 of the piston 9 is provided a port 27 which, in the reciprocating travel of the piston, is adapted to register with the ports 17 and 18, respectively. The piston 9 acts as a Valve with respect to all of the ports 16, 17 and 18 of the charging cylinder.

In practice, the inlet port 16 is communicative-1y connected by means of a pipe, secured within the opening 28, with a carburetor of known or suitable construction; and the spent gases, smoke, etc, are discharged from the power cylinder 5 by means of a delivery pipe connected within the opening The engine body may be of any suitable design, being provided with water cooling chambers or, as shown, with external fins 30 for air cooling.

In the following description the piston 9 of the charging cylinder will, for convenience of explanation, be designated as the plunger.

Operation: A fuel-mixture charge or a portion of a charge is sucked through the port 16 from the carburetor into the charging cylinder 6 above the plunger-wall 26 in each down stroke of the plunger after the latter has descended to below said intake port. During such suction stroke of the plunger the piston 8 is moving upwardly to re-compress the charge supplied thereinto in the preceding cycle of the engines operation.

As the piston approaches or has reached the end of its Lip-stroke the charge is ignited causing an explosion of the charge which drives the piston downwardly. When the explosion occurs ports 14 and 15 are closed by the piston. As the piston descends the plunger ascends until about one-half of its tip-stroke, the port 27 of the plunger, see Fig. 4, communicates with the by-passage port 18 for the escape of partially com pressed fuel from the charging cylinder through the by-passage 18 19 into the power cylinder to effect the displacement of the spent gases from the latter through the exhaust ports 15 which have meanwhile been uncovered by the piston 8. The

- plunger continuing its upward travel closes port 18 and opens port 17 with respect to plunger port 27, whereupon the gases fully compressed (as far as the charging cylinder is concerned) escapes through passage 19 directly into the power cylinder. This transfer of the gases occurs when the piston 8 and plunger 9 occupy substantially the relative positions in which they are represented in Figs. 1 and 2-that is to say, with the piston starting upwardly and the plunger at or near the upper end of its travel.

By arranging the piston to have a lead of approximately 15, circular measure, and by reason of locating the port 17 to be fully open with respect to the port 27 of the plunger when the latter is at the top of its stroke, the plunger-which moves at a slower speed than the piston-does not close the port 17 until the exhaust port 15 is closed, or nearly so, by the piston. Following the closing of ports 15 and 17, the movements of the plunger and piston, respectively, effect a slight reduction of pressure in the charging cylinder and a slight increase of pressure in the power cylinder until the plunger port 27 reaches the by-passage port 18, whereupon a reverse flow. of gases from the power cylinder into the charging cylinder occurs and which continues until the piston covers the port 14.

After this port is closed the continued upward travel of the piston recompresses the charge remaining in the power cylinder.

The extent of such re-compression in the power cylinder is dependent upon the regulation afforded by the bypass valve 20, ranging from about in the proportion of three to one when the by-pass is fully open to five to one when it is fully closed, intermediate pressure being obtainable by partially closing the by-pass valve.

An advantage of the invention is in the substantially complete scavenging action of the incoming fuel mixture due to its upward whirling motion above referred to which is brought about by the relative arrangement of the intake passage 19 with its helically disposed orifice or port 14.

After the spent gases are expelled from the power cylinder, all or a part of the fuel mixture, which has been employed to displace the exhausted spent gases, may be further compressed in the power cylinder (when the by-pass valve 20 is closed) or a portion of such fuel mixture may be re turned to the charging cylinder (when the alve 20 is open) thereby permitting the engine to be operated by the explosion of gases under different degrees of pressure.

The fuel gases which are fired are practically uncontaminated by-any spent gases, which is also true with the fuel gases which are returned to the charging cylinder, which is a big advance in the art.

The circulation of the gases, moreover, has a cooling effect upon the engine to an extent which permits the engine to operate at a high efiiciency without the use of cooling water and fan-induced air currents as hitherto deemed necessary.

The manner of applying my invention and its mode of operation will it is believed be understood from the foregoing description. While I have illustrated and explained the embodiment of my invention now preferred by me, I do not wish to be understood as confining the invention specifically thereto as changes may be made without departing from the spirit of the invention within the scope of the appended claims.

hat I claim, is,-

1. In an internal combustion engine of the two-cycle type having a power cylinder and a separate charging cylinder communicating therewith, and means cooperating with the pistons in the respective cylinders for controlling, first, the admission of the combus tible mixture into the power cylinder; second, the discharge of the exhaust gases from the power cylinder; and third, after closing the exhaust to atmosphere, regulating by means 013 exhaust gases from the power cylinder the amount and pressure of the charge mixture retained in the power cylinder at the time communication between said power and charging cylinders is closed by the piston of the charging cylinder.

2. In an internal combustion engine of the two-cycle type having a power cylinder and a separate charging cylinder in which a carbureted air charge is mixed and heated by compression before entering the power cylinder, of means including pistons in the respective cylinders for controlling, first, the admission of the combustible mixture into the power cylinder, second, the discharge of exhaust gases into the atmosphere from the power cylinder, and third, maintaining the charge mixture admitted into the power cylinder at approximately atmospheric pressure by means of exhaust gases from the power cylinder after closing the exhaust to the atmosphere and until communication between said power and charging cylinders is closed by the piston of the charging cylinder.

3. In an internal combustion engine of the two-cycle type having a power cylinder and a separate charging cylinder provided with an inlet port, and two exhaustrports communicating with said power cylinder, one of said exhaust ports communicating through a manually operated controlling valve with the inlet port of the power cylinder, whereby the power output of the power cylinder is regulated and the degree of scavenging the power cylinder is kept substantially constant at all powers.

4. In an internal combustion engine of the two-cycle type having a power cylinder and a separate charging cylinder, said power cylinder being provided with a charge mixture inlet-port and an exhaust port, a power piston also serving as a valve for both of said ports, the location of said ports being such that said piston during its power stroke uncovers the inlet port first then the exhaust port and during its compression stroke successively closes the exhaust and intake ports, means to render the intake port inoperative during the power stroke, means for supplying a charge mixture to said intake port during the last part of the power stroke and the first part of the compression stroke of said piston, and means to regulate the degree of compression and prevent compression commencing in the power cylinder before the power piston has closed said intake port.

5. In an internal combustion engine of the two-cycle type, having a power cylinder and a separate charging cylinder, said power cylinder having an inlet port and an exhaust port, said charging cylinder having an inlet port and two exhaust ports, pistons provided in the respective cylinders, said pistons serving as valves for the respective ports, means to control said pistons whereby the opening and closing of said ports is timed to produce a relatively short compression period and a relatively long expansion period in the power cylinder, and a manually operated valve disposed between the exhaust ports of said charging cylinder and the inlet port of said power cylinder, said valve serving to regulate the amount of charge retained in said power cylinder.

Signed at Seattle, Washington, this 22nd day of January, 1926.

OLAF HETLESATER. 

